#include <bits/stdc++.h>
using namespace std;
#define LL long long
#define XH(i,a,b) for(int i = a; i < b; ++i)
#define XXH(i,b,a) for(int i = b; i >= a; --i)
#define Module 998244353
int tmpInt;LL tmpLL;string tmpStr;char tmpChar;
vector<int>tmpIntVector;

int main(){
  string S;
  cin>>S;
  XH(i,0,S.size()){
    if((i+1)%2 == 1 && S[i]>='A'&&S[i]<='Z'){
      cout<<"No"<<endl;
      return 0;
    }else if((i+1)%2 == 0 &&S[i]>='a'&&S[i]<='z'){
      cout<<"No"<<endl;
      return 0;
    } 
  }
  cout<<"Yes"<<endl;
  return 0;
}
